Water purification system engineered for Legionella control in industrial and commercial water systems

ABSTRACT

The present invention relates to water purification systems and uses thereof. In particular, the present invention relates to the use of water filtration systems to combat  Legionella  bacterial contamination of industrial and commercial water systems, such as grocery store misting systems.

The present application is a continuation of U.S. patent applicationSer. No. 13/975,003, filed Aug. 23, 2013, which claims priority to U.S.Provisional Patent Application Ser. No. 61/692,494, filed Aug. 23, 2012,the entire disclosures of which are herein incorporated by reference intheir entireties.

FIELD OF THE INVENTION

The present invention relates to water purification systems and usesthereof. In particular, the present invention relates to the use ofwater filtration systems to combat Legionella bacterial contamination ofindustrial and commercial water systems, such as grocery store mistingsystems.

BACKGROUND OF THE INVENTION

Legionella is a genus of Gram-negative bacteria comprising many speciesand distinct antigenic types with Legionella pneumophila being the mostcommon pathogenic species. Legionaires' disease is the common name for avariety of diseases resulting from infection by Legionella bacteria. Themost common presentation of many Legionella species is acute pneumonia(legionellosis), but many species of the bacteria are also capable ofcausing an influenzalike illness known as Pontiac fever (Winn, W. C. Jr.(1996). Legionella (In: Baron's Medical Microbiology, Baron, S. et al.,eds. (4th ed.). University of Texas Medical Branch).

Legionella species are widely present in environmental water suppliessuch as rivers, lakes, and drinking water. To prevent infection by thesebacteria, water is often disinfected with chlorine or heat, but bacteriaoften remain following these treatments. Of particular concern arenosocomial infections by these bacteria, given that many hospital watersupplies have been demonstrated to contain Legionella bacteria.Hospitals expend a large amount of resources on a variety ofdisinfectant methods to reduce Legionella infections (Yu V L, InfectionControl and Hospital Epidemiology (2011) 32(2). Controlling Legionellain Hospital Drinking Water: An Evidence-Based Review of DisinfectionMethods).

Other known environmental sources of Legionella bacteria includeswimming pools, evaporative condensers, cooling towers, nebulizers,humidifiers, ornamental fountains, and whirlpool spas. Dissemination ofbacteria from environment to host generally requires aerosolization ofthe contaminated water. The contaminated water in the aforementionedsources can be aerosolized incidentally, for example during toiletflushing, or by design, as seen in nebulizers and fountains. Inhalationof these bacterial aerosols is thought to lead to the acute pneumoniaobserved in patients exhibiting legionellosis.

Recognizing the public health concerns posed by Legionella bacteria, theAmerican Society of Heating, Refrigerating and Air-ConditioningEngineers (ASHRAE) established a Standard Practice for use by facilitymanagers and owners to prevent Legionella contamination in buildingwater systems. This standard, known as ASHRAE Standard 188P, specifies apractice to identify the conditions in a water system that can be madeless favorable to the growth and transmission of Legionella. To optimizethe advice given in this report, Hazard Analysis and Critical ControlPoint (HACCP) plans were used.

What is needed are new systems for addressing public health risksassociated with Legionella bacteria.

SUMMARY OF THE INVENTION

The present invention relates to water purification systems and usesthereof. In particular, the present invention relates to the use ofwater filtration systems to combat Legionella bacterial contamination ofindustrial and commercial water systems, such as grocery store mistingsystems.

For example, in some embodiments, the present invention provides asystem for killing, removing, or slowing the grown of bacteriacomprising: a water softener, a carbon filter, a reverse osmosiscomponent, a purified water storage vessel, a recirculating pump, anultraviolet light disinfection component, a final filtration component,specialized distribution piping, and a nozzle.

When produced and maintained as prescribed in this application, thepurified water system described herein is compliant with the ASHRAEStandard 188P. If the steps described herein are followed, Legionellabacterial loads in the water are drastically reduced.

In some embodiments, the invention is a method for reducing orpreventing Legionella bacterial contamination of a water supply systemcomprising: passing a fluid through a water softening component, passingthe effluent from the water softening component through a carbonfiltration component, passing the effluent from the carbon filtrationcomponent through a machine capable of reverse osmosis, passing theeffluent from the machine capable of reverse osmosis through a storagevessel, passing the effluent from the storage vessel through arecirculating pipe, passing the effluent from the recirculating pipethrough an ultraviolet light component, passing the effluent from theultraviolet light component through a final filtration, contacting theeffluent from the final filtration with distribution piping, andcontacting the distribution piping with a nozzle. In some embodiments,the water softening component comprises two units which operatealternately. In some embodiments, the storage vessel is airtight exceptfor a 0.2-micron vent filter. In some embodiments, the recirculatingpump delivers a minimum of 3 feet per second flow velocity. In someembodiments, the final filtration utilizes a 0.2 micron filter. In someembodiments, the distribution piping circulates returns some of thefluid from the final filtration component to the storage vessel. In someembodiments, the conductivity of the fluid is measured at one or moretimes.

In some embodiments, the invention is a method of providing purifiedwater to grocery store misting systems comprising: passing a fluidthrough a water softening component, passing the effluent from the watersoftening component through a carbon filtration component, passing theeffluent from the carbon filtration component through a machine capableof reverse osmosis, passing the effluent from the machine capable ofreverse osmosis through a storage vessel, passing the effluent from thestorage vessel through a recirculating pipe, passing the effluent fromthe recirculating pipe through an ultraviolet light component, passingthe effluent from the ultraviolet light component through a finalfiltration, contacting the effluent from the final filtration withdistribution piping, and contacting the distribution piping with anozzle. In some embodiments, the water softening component comprises twounits which operate alternately. In some embodiments, the storage vesselis airtight except for a 0.2-micron vent filter. In some embodiments,the recirculating pump delivers a minimum of 3 feet per second flowvelocity. In some embodiments, the final filtration utilizes a 0.2micron filter. In some embodiments, the distribution piping circulatesreturns some of the fluid from the final filtration component to thestorage vessel. In some embodiments, the conductivity of the fluid ismeasured at one or more times.

In some embodiments, the invention is a system for providing purifiedwater to grocery store misting systems comprising: a fluid inlet meansfor introducing a flow of water, a water softening component, a carbonfiltration component, a reverse osmosis component, a water storagevessel, a recirculation pump, a conductivity meter, an ultraviolet lightproducing unit, a final filter with pores no larger than 0.2 microns,and distribution piping capable of attaching to a misting nozzle. Insome embodiments, the water softening component contains two units whichoperate alternately. In some embodiments, the water storage vessel isairtight except for a 0.2-micron vent filter. In some embodiments, theentire contents of the water storage vessel is exposed to ultravioletlight and/or filtration every 30 minutes.

DESCRIPTION OF THE FIGURE

FIG. 1 shows a diagram of one exemplary embodiment of the inventiondescribed herein.

DEFINITIONS

To facilitate an understanding of the present invention, a number ofterms and phrases are defined below.

The term “sample” as used herein is used in its broadest sense. A samplemay comprise any biological, industrial, or environmental material,including, but not limited to, water samples from any source.

As used herein, the term “filter” includes any substance through which aliquid or gas can be passed to remove impurities. The filter can be madeof paper, cloth, sand, carbon, and many other substances. In a moregeneral sense, filtering can include any process that removes particles,ions, molecules, or other pieces of matter from a fluid. “Filter” can beused as a verb to mean “passing a fluid through a filter.” “Filteringout” can be a verb meaning “removing impurities with a filter.”“Filtering” can also be referred to as “filtration.”

As used herein, the term “produce” includes any agricultural product,especially fruits and vegetables. Many grocery stores contain producesuch as broccoli, lettuce, berries, squash, spinach, and the like.

As used herein, the term “misting” includes water and any other liquidfinely suspended in air. In the context of grocery stores, misting ofwater is often used on food such as produce to maintain a freshappearance. Restaurants and other commercial and industrial businessesuse misting in public areas for cooling of people or animals.

As used herein, the term “aerosolize” includes any process thatdisperses a liquid into a gas in tiny suspended droplets. One specificuse of the word “aerosolize” refers to the process by which bacteriaenter the air, potentially leading to inhalation of the bacteria.

As used herein, the term “grocery store” and “supermarket” are used toinclude any place where foodstuffs and various household supplies aresold.

As used herein, “tap water” includes any water that is drawn from thepipes in a building. “Tap water” includes municipal water and wellwater.

As used herein, “recirculating pump” includes any device that causes afluid to have a current and causes the effluent fluid to return in fullor in part to said device. The term “purified water recirculation pump”refers to a type of recirculating pump. In some embodiments referred toherein, a purified water recirculation pump delivers a minimum of 3 feetper second flow velocity in the fluid and operates continuously.

As used herein, the term “water softener” includes any process thatreduces the concentration of calcium, magnesium, and other ions inwater. The removal of the ions during this process makes the water morecompatible with soaps and less likely to cause fouling of plumbing.There are many methods of water softening but one common method uses anion-exchange resin to exchange the calcium, magnesium, and other ionsfor sodium ions.

As used herein, the term “carbon filtration” includes any method offiltering that uses activated carbon to remove contaminants andimpurities. Specifically, chlorine, chloramines, sediments, and otherorganic compounds can be removed from a fluid by carbon filtration.Activated carbon contains many pores and thereby a large surface area.The iodine number of activated carbon describes the adsorption capacityof the carbon.

As used herein, the term “reverse osmosis” includes any process thatfilters out large molecules and ions from a fluid by applying pressureto fluid on one side of a selective membrane. Given a membrane withproper pore size, the aforementioned application of pressure will causethe solvent to be purified on the side of the membrane opposite thepressure while large molecules and ions will remain on the side to whichpressure is being applied. Reverse osmosis can be used to create waterof very high purity.

As used herein, the terms “purified” or “to purify” refer, to theremoval of undesired components from a sample. In a relative sense, asubstance is purified if it contains fewer undesired components than ithad at a previous point in time.

As used herein, the term “conductivity meter” refers to any devicecapable of measuring the electrical conductivity in a solution. As usedherein, conductivity meters are used to determine the level of chemicalimpurities in a sample.

As used herein, the term “impurity” refers to any undesirable componentin fluids and solids. Some examples of impurities found in a fluidinclude ions, particles, organic compounds, and particular molecules.

As used herein, the term “ultraviolet disinfection” refers to theprocess by which electromagnetic radiation with a wavelength shorterthan visible light but longer than X-rays in the range of 10-400 nm isapplied to a sample for a duration. If the wavelength and duration areselected appropriately, this process can drastically reduce themicrobial load of a sample.

As used herein, the term “microbial load” refers to the relative orabsolute amount of microbes within a sample.

The terms “bacteria” and “bacterium” refer to all prokaryotic organisms,including those within all of the phyla in the Kingdom Procaryotae. Theterm is intended to refer to members of the Legionella genus. It isintended that the term encompass all microorganisms considered to bebacteria including Mycoplasma, Chlamydia, Actinomyces, Streptomyces, andRickettsia. All forms of bacteria are included within this definitionincluding cocci, bacilli, spirochetes, spheroplasts, protoplasts, etc.Also included within this term are prokaryotic organisms that are gramnegative or gram positive. “Gram negative” and “gram positive” refer tostaining patterns with the Gram-staining process that is well known inthe art. (See e.g., Finegold and Martin, Diagnostic Microbiology, 6thEd., CV Mosby St. Louis, pp. 13-15 [1982]). “Gram positive bacteria” arebacteria that retain the primary dye used in the Gram stain, causing thestained cells to appear dark blue to purple under the microscope. “Gramnegative bacteria” do not retain the primary dye used in the Gram stain,but are stained by the counterstain. Thus, gram negative bacteria appearred. In some embodiments, the bacteria are those capable of causingdisease (pathogens) and those that cause production of a toxic product,tissue degradation or spoilage.

As used herein the term “biofilm” refers to an aggregation ofmicroorganisms (e.g., bacteria) surrounded by an extracellular matrix orslime adherent on a surface.

As used herein, the term “pathogen” refers to a biological agent thatcauses a disease state (e.g., infection, cancer, etc.) in a host.“Pathogens” include, but are not limited to, bacteria, fungi, archaea,protozoans, nematodes, mycoplasma, and other parasitic organisms.

As used herein, the term “microorganism” refers to any species or typeof microorganism, including but not limited to, bacteria, archea, fungi,protozoans, mycoplasma, and parasitic organisms. The term “microbe” islargely equivalent to the term “microorganism.”

As used herein, the term “distribution piping” refers to any system ofpipes that delivers water from a water source such as a municipal watersupply or purified water storage vessel to a point of use. In someembodiments, “distribution piping” refers to a system in which the wateris continually circulating from the storage vessel to the points of useand back to the storage vessel with no dead legs larger than 20 pipediameters.

As used herein, the term “point of use,” in reference to water, refersto any location where water is used. Potential points of use include butare not limited to water faucets, misting systems, drinking fountains,irrigation systems, and whirlpool water supplies.

As used herein, the term “dead leg” refers to any section of piping thatdoes not receive significant flow. These pockets of largely undisturbedfluid provide suitable conditions for growth and reproduction of manyspecies of microbes including Legionella bacteria.

As used herein, the term “pipe” refers to any hollow body capable ofconducting a fluid. The terms “tube” and “piping” are largely similar tothe term “pipe.”

As used herein, the term “preventative maintenance” refers maintenance,including tests, measurements, adjustments, and parts replacement,performed specifically to prevent faults from occurring.

As used herein, the term “nozzle” refers to any device used to controlthe direction or characteristics of a fluid flow as it exits or entersan enclosed chamber or pipe via an orifice. Nozzles are often used toincrease the velocity of a flow at the point of use.

As used herein, the term “airtight” refers to the quality of beingimpervious to air or other fluids.

As used herein, the term “fluid” refers to any substance that has nofixed shape. Generally fluids also yield easily to external pressure andflow easily.

DETAILED DESCRIPTION OF THE INVENTION

Legionella is a genus containing many species of bacteria that arepathogenic to humans. Since the discovery of Legionella pneumophila inthe 1970's, this genus has expanded to include many species including:Legionella adelaidensis, Legionella anisa, Legionella beliardensis,Legionella birminghamensis, Legionella bozemanii, Legionella brunensis,Legionella busanensis, Legionella cherrii, Legionella cincinnatiensis,Legionella donaldsonii, Legionella drancourtii, Legionella drozanskii,Legionella erythra, Legionella fairfieldensis, Legionella fallonii,Legionella feeleii, Legionella geestiana, Legionella genomospecies,Legionella gratiana, Legionella gresilensis, Legionella hackeliae,Legionella impletisoli, Legionella israelensis, Legionellajamestowniensis, Legionella jeonii, Legionella jordanis, Legionellalansingensis, Legionella londiniensis, Legionella longbeachae,Legionella lytica, Legionella maceachernii, Legionella micdadei,Legionella moravica, Legionella nautarum, Legionella oakridgensis,Legionella parisiensis, Legionella pneumophila, Legionella quateirensis,Legionella quinlivanni, Legionella rowbothamii, Legionella rubrilucens,Legionella sainthelensi, Legionella santicrucis, Legionellashakespearei, Legionella spiritensis, Legionella steigerwaltii,Legionella taurinensis, Legionella tucsonensis, Legionella wadsworthii,Legionella waltersii, Legionella worsleiensis, Legionella yabuuchiae.

The clinical relevance of Legionella first came to light during anoutbreak of what came to be known as Legionairres' disease in 1976.During this initial outbreak, as many as 221 individuals experiencedsymptoms ranging from pneumonia to chest pain, and 34 deaths wererecorded. The outbreak was traced to Legionella pneumophila in a hotelair conditioning system. Currently, legionellosis is known to cause twodistinct conditions. Legionnaire's disease, also known as Legion Fever,leads to fever and pneumonia while Pontiac fever leads to a less severerespiratory illness more similar to acute influenza than pneumonia.Legionairres' disease has become a condition of great public healthconcern. In fact, the Massachusetts Department of Public Health Bureauof Communicable Disease Control estimates that the overall case-fatalityrate is 5-30%. Furthermore, the disease is thought to affect 8,000 to18,000 individuals each year in the United States, with L. pneumophilabeing the primary agent of infection.

Legionella bacteria are present at low levels in the environment in manylocations where freshwater is present including lakes and streams.Optimal conditions for growth include temperatures of about 30° C.-50°C. (86° F.-122° F.), stagnant water, presence of amoebae which can serveas hosts for the bacteria, and presence of rust and scale. Given theseoptimal growth conditions, it is not surprising that Legionellaoutbreaks often occur in locations such as water heaters, waterdistribution systems, fountains, spa baths, swimming pools, humidifiers,cooling towers, and air and water handling systems. As the Legionellabacterial load rises in a water source, transmission to humans becomesincreasingly likely. This transmission to humans is thought to requireaerosolization of the water. For this reason, nebulizers and othermisting devices can be particularly effective transmission devices forLegionella bacteria. In some embodiments, the invention described hereinrelates to methods and systems for preventing or reducing the spread ofLegionella bacteria, for example, in grocery store produce misters andother commercial and industrial water systems. It will also beappreciated that these system further find use in the reduction of otherbacterial and bioagents in water systems. As such, reduction of foulingand biofilm formation are provided.

In some embodiments, the spread of Legionella bacteria is reduced orprevented with effective water filtration systems and methods. In someembodiments, provided here is a produce misting system comprising one ormore or all the following components: a water softener, a carbon filter,a reverse osmosis filter, a water storage vessel, a recirculation pump,a conductivity meter, an ultraviolet light producing unit, a finalfilter, specialized distribution piping, and a misting nozzle.

In some embodiments, tap water is brought into the system via a fluidinlet. This component can comprise any means of delivering water to thesystem. For example, in some embodiments the fluid inlet is a hose whichcarries tap water. In other embodiments, the fluid inlet is a tube.

In some embodiments, the water softening component comprises resin bedswhich reduce the concentration of certain metal ions including calciumand magnesium which are naturally present in many tap waters. In someembodiments, these metal ions are replaced with sodium ions which areless likely to accumulate on plumbing and interfere with detergents. Insome further embodiments, the water softener is engineered in aduplex-twin alternating fashion in order to provide water to the system24 hours per day and regenerate the resin on a frequent basis. In suchembodiments, while one of the water softening twins is in a regenerationcycle, the other twin is on-line providing soft water to the system. Insome embodiments, the resin is regenerated by concentrated brinecontaining one or more of the following: sodium chloride, potassiumchloride, and hydrochloric acid. In other embodiments, the watersoftening is performed by a single softening unit or a plurality oftandem units.

Carbon filters use activated carbon to remove contaminants andimpurities from a fluid or solution. This process utilizes chemicaladsorption, a process by which particles, atoms, ions, or moleculesadhere to a surface, in this case activated carbon. In some embodiments,carbon is used to filter out chlorine, chloramines, and organicimpurities from incoming water in a purified water system. Onecomplication of utilizing an organic component such as activated carbonin a water filtration system is microbial contamination. In someembodiments, disinfected portable exchange carbon canisters and virginacid washed carbon are utilized each time the carbon filter is exchangedin the system. In some embodiments, the carbon canisters are bacteriatested and validated with the QSR procedure TWTS 000010SO, a carbondisinfection procedure. The pore volume available in the activatedcarbon is often denoted with iodine numbers. In some embodiments,activated carbon with an iodine number of 900 or greater is utilized inthe system.

Reverse osmosis is a filtration technique that can be used to createhigh-purity water. This well-established technique involves applicationof pressure to fluid on one side of a selectively permeable membrane.Given a properly sized membrane, this process concentrates the fluid onthe side of the membrane opposite the pressure. In some embodiments,reverse osmosis is used as a component of the filtration system. In ourexperiments, we have determined that a reverse osmosis unit that startsand stop frequently for short periods of time results in poor rejectionof inorganic and organic substances, ultimately increasing the microbialcontent of the purified water treatment system. In some embodiments, thereverse osmosis unit is custom engineered to activate and remain activefor a maximum period of time in order to assist in rejection and controlof Legionella bacteria in the system.

In many of the current grocery store purified water misting systems, thestorage vessels have bladder-style configurations. This design allowspurified water to stagnate and serve as an excellent medium forbacterial growth. In some embodiments, the storage vessel contains acone-shaped bottom portion and a domed top. Furthermore, in someembodiments the vessel is completely sealed except for a hydrophobic0.2-micron vent filter. In some embodiments, this vent filter preventsairborne bacteria from entering the vessel, allowing the vessel tobreathe in an aseptic fashion. In some further embodiments, the storagevessel is engineered to carry the minimum amount of water required tokeep up with the demand at the point of use. In some other embodiments,this optimally small inner surface area assists ongoing Legionellabacteria control. In some embodiments, the entire amount of purifiedwater in the storage vessel is treated with bacteria control equipmentsuch as ultraviolet light and a final filtration step approximatelyevery 30 minutes in order to reduce Legionella bacterial load.

Another problem with many purified water systems is water stagnation.When water remains still for a long period of time it serves as anexcellent environment for growth of bacteria including species ofLegionella. In the current grocery store purified water treatmentsystems, water is not recirculated. In this case, if the points of useare not using water, the water remains static, adding to the microbialload in the system. Some embodiments of the present invention addressthis concern with a purified water recirculation pump. In someembodiments, the pump is engineered to deliver a minimum of 3 feet persecond flow velocity. Furthermore, in some embodiments, the pumpdelivers this high pumping velocity 24 hours per day without ceasing inorder to control Legionella bacterial loads in the purified water loop.

In order to insure that a water purification system is functioningproperly, a method of determining the quality of the water, in someembodiments, is included. When microbial content in water increases,electrical conductivity also increases. Conductivity of water istherefore a proxy for level of bacterial contamination. Some embodimentsof the present invention determine the quality of the water that is fedto the points of use using a conductivity meter. In some embodiments,the present invention uses conductivity monitoring continuously 24 hoursper day, seven days per week to insure high water quality in thepurified water loop of the purification system. In some embodiments,readings above a preselected threshold level set off an alarm orwarning. The system can then be cleaned or an automatic decontaminationprocedure can be initiated (e.g., via computer control).

One further shortcoming of current grocery store purified water mistingsystems is a lack of bacterial control equipment in the purified waterpiping systems. The pipes that lead the purified water to the point ofuse and back to the storage vessel (purified water distribution piping)are critical and capable of drastically increasing the bacterial load atthe point of use if they are not disinfected. In some embodiments,ultraviolet disinfection is used in the purified water distributionpiping in order to further reduce the microbial load, particularlyLegionella, at the point of use. In some embodiments, ultraviolet light(e.g., with a wavelength of 254 nm) is used in order to kill bacteria orrender them unable to reproduce. In other embodiments, the ultravioletdisinfection system is specifically engineered and sized for each systemto meet the distribution system flow requirements. In some embodiments,ultraviolet disinfection is only employed if the system detects thepresence of undesired (e.g., any) levels of bioagent in the watersystem.

Current grocery store purified water misting systems utilize no bacteriacontrol equipment in the purified water distribution piping systems. Toensure delivery of highly purified water, some embodiments of thepresent invention include a final filtration step. To perform thisfiltration, some embodiments of the systems and methods include a filter(e.g., a 0.2-micron) which serves to filter Legionella bacteria. In someembodiments, the final filters are absolute rated. In some embodimentsthe final bacteria removal filters are installed in a manner such thatthey receive fluid after it has been treated with ultraviolet light.

Current grocery store purified water misting stems are generally deadleg piping systems that do not recirculate the water from the point ofuse back to the storage vessel. When the purified water remainsundisturbed, Legionella bacteria are able to reproduce and a biofilm canbegin to accumulate. To minimize undisturbed water, some embodimentsinclude no dead legs longer than 20 pipe diameters. In some otherembodiments, the systems and methods employ distribution piping that isopaque in order to reduce the ambient light that reaches the purifiedwater. This light can heat the water and make it more conducive toLegionella bacteria reproduction. Some embodiments of the systems andmethods employ flexible distribution piping. In order to provide watermisting to produce in grocery stores, some embodiments of the systemsand methods employ a misting nozzle attached directly or indirectly tothe distribution piping. In some embodiments, this nozzle turns thewater from the filtration system into a fine mist which enhances theaesthetic appeal of the produce receiving the mist.

In the exemplary embodiment shown in FIG. 1, water enters the systemthrough piping connected to a water softening component. Said waterfiltration device is connected via additional piping to a carbonfiltration component. The carbon filtration component is connected to areverse osmosis via further piping. Additional piping is attached to thecarbon filtration component at one end and a storage tank at the otherend. This storage tank is connected to a water pump with additionalpiping. The water pump is connected to an outlet pipe which is furtherconnected to final filters. A UV light device is also connected to thispipe. Additional piping is attached to the final filters. This piping isattached to both the points of use and the aforementioned storage tank.

To help insure that the purified water misting system is continuallyable to minimize Legionella bacteria and maintain its ASHRAE Standard188P validation, some embodiments described herein include bi-annual andannual preventative maintenance including carbon, filter, and bulbreplacements. In addition, some embodiments of the invention employ anannual distribution piping disinfection to meet the Total WaterTreatment Systems QSR Procedure TWTS000001TM “Water System Storage Tankand/or Pipeline Sanitization.”

EXPERIMENTAL

The following example is provided in order to demonstrate and furtherillustrate certain preferred embodiment and aspects of the presentinvention and is not to be construed as limiting the scope thereof.

Example 1

To test this invention, one preferred embodiment was constructed. Inthis test, water entered the system and was processed by a duplex-twinalternating water softener. The softened water was then passed through acarbon filter with activated carbon with an Iodine number of 900 orgreater. Next, the water passed through a membrane via reverse osmosis.Next, the water was stored in a large tank with a vent filter with poresno larger than 0.2 microns that fed water into the distribution pipingsystem. Water next left the tank, underwent repressurization to achievea flow of 3 feet per second, ultraviolet light disinfecting, and a finalfiltration through a filter with 0.2-micron pores. Finally, the waterwas delivered to a nozzle at the point of use, and unused water isdirected back to the storage tank. Water was withdrawn from this nozzleand tested for Legionella contents with the Phigenics PVT PlusLegionella testing standard. This test found that this specificembodiment was very effective at removing Legionella bacteria from thetest water.

All publications and patents mentioned in the above specification areherein incorporated by reference. Various modifications and variationsof the described method and system of the invention will be apparent tothose skilled in the art without departing from the scope and spirit ofthe invention. Although the invention has been described in connectionwith specific preferred embodiments, it should be understood that theinvention as claimed should not be unduly limited to such specificembodiments. Indeed, various modifications of the described modes forcarrying out the invention which are obvious to those skilled in therelevant fields are intended to be within the scope of the followingclaims.

We claim:
 1. A method for reducing or preventing Legionella bacterialcontamination of a water supply system comprising: a) passing waterthrough a reverse osmosis component; b) passing the effluent from a)through a water storage vessel, wherein the water storage vessel isairtight except for a microporous vent filter on said water storagevessel; and c) passing the effluent from b) through a recirculating pumpthat delivers a minimum of 3 feet per second flow velocity and thatcirculates water in a continuous cycle from said storage vessel, throughan ultraviolet light, through a final filter, and to a distributionpiping, wherein water not distributed to a point of use via saiddistribution piping is returned to said storage vessel.
 2. The method ofclaim 1, wherein said water passed through said reverse osmosiscomponent is first passed through a carbon filtration component.
 3. Themethod of claim 1, wherein the microporous vent filter is a 0.2-micronvent filter.
 4. The method of claim 1, wherein the final filtrationutilizes a 0.2 micron filter.
 5. The method of claim 1, wherein theconductivity of the water is measured at one or more times.
 6. A methodfor reducing or preventing Legionella bacterial contamination in apurified water supply system providing purified water to a grocery storemisting system comprising: a) passing water through a reverse osmosiscomponent; b) passing the effluent from a) through a water storagevessel, wherein the water storage vessel is airtight except for amicroporous vent filter on said water storage vessel; and c) passing theeffluent from b) through a recirculating pump that delivers a minimum of3 feet per second flow velocity and that circulates water in acontinuous cycle from said storage vessel, through an ultraviolet light,through a final filter, and to a distribution piping, wherein water notdistributed to a point of use via said distribution piping is returnedto said storage vessel.
 7. The method of claim 6, wherein said waterpassed through said reverse osmosis component is first passed through acarbon filtration component.
 8. The method of claim 6, wherein themicroporous vent filter is a 0.2-micron vent filter.
 9. The method ofclaim 6, wherein the final filtration utilizes a 0.2 micron filter. 10.The method of claim 6, wherein the conductivity of the water is measuredat one or more times.